How to answer MCQs
studentBMJ 2005;13:89-132 March ISSN 0966-6494
Multiple choice questions (MCQs) are set by most medical schools in examinations and often form a substantial component of written final exams. Many prize exams and postgraduate medical exams also incorporate MCQs into their assessments.
The most commonly used MCQ format is a stem question followed by five statements, each of which must be answered true, false, or dont know. Scoring MCQs may involve negative marking--a term which strikes fear into the heart of medical students the world over--in which one mark is awarded for a correct answer, one mark deducted for an incorrect answer, and no mark awarded or deducted for dont know.
Each year, students may unexpectedly fail written exams despite extensive preparation, not through lack of knowledge or intelligence, but simply because of poor exam technique. Candidates often find themselves leaving an MCQ exam completely unsure of how they have done. The way students approach MCQs, and their technique of answering, is important.
The preparation required for an MCQ paper is different to that for an essay paper. For an essay paper, it is often possible to question spot commonly recurring topics and to plan your revision accordingly. But this is often not possible for MCQ examinations, in which the sheer quantity of questions tests a much broader range of the syllabus. One of the best ways of revising for MCQs is to read as widely around a subject as possible, concentrating less on memorising hard facts and more on understanding basic principles and concepts. This will allow you to stand a greater chance of working out answers to MCQs from first principles.
If you can, try to work through previous MCQ papers as these will give you the best indication of the style of each particular examination. If there is a limited pool of questions, they may even be repeated in the exam. Some students find specialist MCQ books useful for practise, although it should be borne in mind that the question style and range of topics found in such books will often differ substantially from the specific exam to be taken.
Always calculate the time available for each question before the exam and stick to that time strictly. Do not allow yourself to become delayed by any single question. Instead, answer the question using your first impression and mark the question with a star so you can return to it.
After finishing your first run through the all questions, you should then start a second run returning to those questions which you have starred giving them further consideration.
When an examination paper consists of both MCQs and essays, it is helpful to read the essay questions before tackling the MCQs as this allows you to subconsciously plan the essay. You may be tempted to leave MCQs on topics that you are not confident about blank by answering dont know, fearing that a wrong guess will score negatively and negate the points accrued by correct answers. But you should aim to answer at least 90% (ideally 100%) of MCQs in every paper. There are extremely few MCQs for which an educated guess will not increase your chance of a correct answer to greater than 50%.
A useful exercise for those unconvinced by such an argument is to get an MCQ book and answer 100 MCQs in your normal manner. Before marking the questions, return to all those left unanswered (or marked dont know) and attempt an educated guess (on a separate sheet of paper) at all of them. You will probably be pleasantly surprised by the gains made using this approach.
Making educated guesses
When faced with an MCQ that you are unsure about, a number of points can help you make an educated guess.
An understanding and familiarity with the key words and phrases that commonly feature in MCQs is vital to maximising your score (table). Questions which include absolute and sweeping statements such as never, always, or exclusively are generally false (because exceptions can be found to virtually any rule). Questions which include the keywords could, possible, or may are more often true than not (after all, anything is possible).
When a question states an exact statistic--for example, the five year mortality after a first myocardial infarction is 12.9% it is often false (as different studies will produce different figures). This general rule does not apply to less precise statistics--the five year mortality after a first myocardial infarct is greater than 5%.
If you encounter a question on a topic which you believe you have a good knowledge of, but the information stated is completely unfamiliar to you, then the chances are that it is false. (For example, if having revised myocardial infarcts you find an MCQ stating Colanss syndrome is a frequent sequelae of myocardial infarction you should answer false as you will not have heard of Colanss syndrome before.)
MCQs are often perceived as being inordinately difficult. But with a planned approach to revision, incorporating a general overview of the syllabus, and careful attention to technique, many questions can be confidently answered correctly and further marks gained by making educated guesses.
Simon D M Chen, specialist registrar in ophthalmology, Oxford Eye Hospital,
studentBMJ 2005;13:89-132 March ISSN 0966-6494